Help with Single photon counter (SPCM AQR 15) for fluorescence detection and trigger a solenoid valve by labview

[John_P1]

The BNC 2120 should have the PFI lines clearly labelled...

Best Regards,

[MatthewTang]

Hi Jeremy,

I think I am facing the data overflow problem....

I have attached my photo of my VI. I would like to ask to prevent Overflow, where should I put my DAQmx Read into? Thank you!

Best,

Matthew

[Prickly_Pear]

In the block diagram that you provided, you are using a DAQ Assistant Express VI. All of the configuration for the DAQ Assistant is inside of the Express VI. This means that the first time that it executes it will start the acquisition with all of the appropriate timing, etc. Every iteration after the first one will behave as if it were a single DAQmx Read VI.

If you are worried about data overflow, try increasing the number of samples to read per iteration. Also, you might consider slowing the acquisition rate down if your application allows it.

Can we talk about your overall application? If I understand this right, you would like to use a single photon counter to trigger a solenoid valve. I believe that it says that the photon counter will output a pulse every time it detects a photon. Is that right? If not, what does it output instead? How is the solenoid triggered? Does it accept a pulse input or is it software triggered? The reason I ask these questions is that I can't understand why you don't just wire the photon counter directly to the solenoid so that it can trigger it without LabVIEW.

Jeremy P.

[johnsold]

Jeremy P.,

Somewhere in this thread it indicates that the pulse from the photon counter are 30 ns long. No solenoid valve can move that fast.

I agree that it has been difficult to determine necessary details.

Lynn

[MatthewTang]

Hi all,

I am not triggering my solenoid valve every time my counter sees a single photon--- instead I have  fluorescent beads flowing through and my counter will received the fluorescent emitted from the beads (whole emission time would be around 5milli sec). If I have lots of beads aligned and flow through, the signal I would expect is roughly a series of square waves.

By this, I would like to use the square waves to trigger my valve, only when it sees a beads that fluoresce.

Hope this could clarify the problem.

Matt

[Prickly_Pear]

Hi Matt,

Can the solenoid accept this square wave as a trigger signal? You would probably need to check to make sure the voltage levels are correct and that the pulse duration is long enough. If not, you could probably do some conditioning to the signal through some hardware so that it can activate the solenoid.

Jeremy P.

[gvalcarcel]

I have already solved this issue with an USB-6218.